Method for the single-step production of vinyl polymers

Abstract

The invention relates to a method and to a reactor for the single-step polymerization of vinyl monomers by a heterogeneous polymerization in bulk by means of organometalic catalysts. A method according to the invention consists in charging a vertical reactor, which is provided with at least two planetary stirrers situated outside the reactor axis, each stirrer formed from a planar centrally-symmetrical two-blade paddle, with a vinyl monomer, the subsequent introduction of an organometalic catalyst in a solution under stirring and in partial doses amounting to 10 -5 to 10 -3 mole up to the final amount of 5×10 -4 to 5×10 -2 mole of catalyst per mole of monomer, stirring of the batch, cutting and disintegration of the formed compact mass with the planetary stirrers and its parallel wiping from the surface of reactor with wiping blades until the batch acquires a powdery form and the resulting product is discharged.

We claim: 
     
       1. A method for the single-step production of vinyl polymers by a non-radical heterogeneous polymerization in bulk under the effect of organometallic catalysts, which comprises: adding a vinyl monomer to a vertical, cylindrical reactor which is provided with at least two planetary stirrers placed outside of the reactor axis each of said planetary stirrers having at least one planar centrally symmetrical two-blade paddle, and means for wiping the sidewalls of said reactor; subsequently introducing into said reactor a solution of an organometallic catalyst under intense stirring in sequential partial doses of size 10 -5  to 10 -3  mole to achieve a total catalyst amount of 5×10 -4  to 5×10 -2  mole of catalyst per mole of the monomer; allowing the monomer to undergo non-radical heterogeneous polymerization under the influence of the organometallic catalyst; intensely stirring the contents of the reactor; cutting and disintegrating any formed compact mass with the planetary stirrers while concurrently wiping the sidewalls of the reactor with said wiping means until the polymer acquires a powdery form; and discharging the powdery product. 
     
     
       2. A method for the single step production of vinyl polymers according to claim 1 wherein said reactor further comprises a combination of planetary stirring equipment and wiping equipment, where said planetary stirring equipment comprises at least two planetary stirrers placed outside of the reactor axis and each of the planetary stirrers comprises a shaft which is mounted onto a common driver, planar centrally symmetrical two-blade paddles, the longitudinal axis of which passes through the rotational axis of the planetary stirrer, said planetary stirrer paddles having their longitudinal axes disposed at an angle ±β of 15° to 20° from the perpendicular of the rotational axis, and oriented about their longitudinal axes towards the plane perpendicular to the rotational axis of the planetary stirrer at an angle ±α of 25° to 35°; and where said wiping equipment comprises at least two wiping blades carried by said driver. 
     
     
       3. A method for the single-step production of vinyl polymers according to claim 2 wherein the planetary stirrer blade paddle portions overlap in the range of 15 to 20% of a fictional cylindrical surface circumscribed by a trajectory of the terminal points of said paddles.